This proves we have been in the millennium since the binding of Satan 2000 years ago. This is a symbolic number representing a long period of time. Revelation is full of symbols.
The book of Revelation consists of a number of parallel recaps relating to the intra-Advent period. Each of these refer to different subjects, entities or aspects of God's unfolding plan during that time. That does not negate the fact that God's dealings with the beast mirrors that of Satan since Christ’s first Advent. For example, the 6th recap (Revelation 17-19) focuses in on Babylon, but also shows the destruction of all the wicked, the beast and false prophet been banished into the Lake of Fire. Satan is simply not the focus of that parallel. The focus of the last recap (Revelation 20) is God's dealing with Satan. Revelation 20 goes right back to the first resurrection (Christ). It finishes with Satan being banished to the Lake of Fire.
The fate of Satan, the beast (spirit of antichrist / mystery of iniquity) and the fallen angels (demons) are all knit together in Scripture. When Satan fell from heaven, so, did all his demons. When Satan was banished from the Garden then all evil was. They also all came under the same spiritual subjugation at the exact same time through Christ’s earthly ministry.
When Christ bound Satan’s kingdom through His life, death and resurrection then all were bound. 2 Peter 2:4, Jude v 6, Revelation 9 and Revelation 20 all prove the whole demonic realm has been restrained from stopping the free-flow of the Gospel. The bruising of the head of the beast (Revelation 13:3, 13:12 and 13:14) correlates with the bruising of the head of Satan 2,000 years ago through the earthly ministry of Christ (Genesis 3:15). They correspond with the spiritual binding imprisoning of Satan during the millennial period. These are figurative metaphors describing the impairment of the kingdom of darkness 2000 years ago.
When Satan was banished from heaven, so was the whole demonic realm (1/3 of the angels went with him).
Through his defeat, Satan fell from heaven (John 12:31 & Revelation 12:7-9) and is now present in the abyss (Revelation 9:1-11 & Revelation 20:3). The abyss is not a physical geographical place. After all, physical metal chains cannot hold spirits. It is a spiritual state of restraint for spirits now. Near the end, the beast will be released from his restraints and the “deadly wound” to his head will be “healed” (Revelation 13:3, 13:12 and 13:14). This tells us that he too was bruised like Satan’s head through the life, death and resurrection of Christ.
Just like Satan’s power and influence were curtailed through the life, death and first resurrection of Christ, so too was the beast’s. The fate of the two mirror each other. The reason is, the beast is dependent upon the power of Satan to do his evil. The beast is his envoy or enforcer. At the end Satan will be released from his restraint to empower the beast to subjugate the Church, curtail the Gospel expanse and deceive the nations again. There will be a suppression of the Gospel in the last of the last days. This will result in deep persecution. But the darkest days in history have always been the brightest days in history.
When Satan is released before the second coming for a little season then so are the beast, and Satan's minions. Satan is promised a freedom from restraint before the second coming, as is antichrist, and every demon. Scripture shows the abyss being opened near the end whereupon Satan and his demons are released from their spiritual restraint (Revelation 9:1-11 and Revelation 20:7). This parallels with the beast also rising from the abyss (Revelation 11:7 and Revelation 17:8). This corresponds with the restraint being taken off the mystery of iniquity in 2 Thessalonians 2:7 before Christ’s return.
Then comes the end! But Christ comes in majestic and eternal glory to overthrow the kingdom of darkness forever. The demonic realm is all killed when Satan is destroyed at the climactic second coming (Isaiah 26:19-27:1, 2 Thessalonians 2:8, Revelation 19:20, 20:9-10). Daniel 7:9-11, 2 Thessalonians 2:8 and Revelation 19:19-20 show this to be the same time when the beast is obliterated.